Log in
Thyroid UK
91,802 members106,069 posts

Can raised ft4 normal ft3 make you tired?

My recent bloods on 100mcg were

Tsh 0.31 (0.27-4.2)

Ft4 25.6 (12-22)

Ft3 5.31 (3.1-6.8)

When first started Levo my tsh was 6.5 and ft3 5.4. It's never been any higher. Still feeling tired so endo increased my t4 to 112.5mcg to see if we could get it higher than my start level.

Still feeling really tired and possibly a little worse. I've only been on it a week so probably can't be the dose increase yet.

But throwing more t4 at me doesn't feel like the answer. He told me to get rt3 checked next time.

For poor converters (not saying that's me) but those who need t3. Could they just keep increasing t4 until they converted enough instead? I feel like thats what his plan is but surely that can't be right?

Thanks

29 Replies
oldestnewest

When your fT4 goes high you start to produce more rT3 because type-1 deiodinase (T4-> T3 and T4 -> rT3) increases and type-2 deiodinase (T4 >- T3 only) reduces. Hence there is little benefit in raising fT4 levels above the upper limit of the reference interval. I would first reduce your levothyroxine to 75 mcg which should give you an fT4 that is near the top of the reference interval. See if you feel better on this dose, if not and if your symptoms are clearly hypothyroid then ask for some liothyronine. I wouldn't bother with an rT3 assay, it will be high on this levothyroxine dose and it's an expensive test. Why pay out a lot of money just to see the blinking obvious?

6 likes
Reply

or convert to NDT and do away with theT4/T3 problem completely?

1 like
Reply

Jimh111....out of interest would high rT3 clear without taking Liothyronine and by just reducing the dose of Levothyroxine? If there’s a T4 to T3 conversation problem wouldn't even a small amount of Levothyroxine convert to rT3? In the past my rT3 has been high along with similar test results to Salphy. My way forward was to stop taking Levothyroxine and take liothyronine as a way to clear it. I’ll point out my dose of Levo back then was much lower than what Salphy is currently on but still I had over range rT3 which I think was the reason I was feeling so ill.

Good luck Salphy I hope you sort this out and feel better soon.

Reply

Rather odd endo...where is he/she trying to get your T3 to? It looks like you are slightly over medicated on T4/levothyroxin as your FT4 is over range. From these results you don't seem to be converting T4 to T3 properly ( ratio well over 4:1). I believe adding more T4 would increase the Reverse T3 , probably making you feel worse, rather than increase FT3. I'd decrease the T4 dose to get a result of 19/20, perhaps to 75 mcg , and ask your endo to give you a T3 medication to at least try(depending what dose of T3 you get you might need to lower T4 dose to 50 mcg too). Has the endo checked B12, D3, folate and ferritin are in the correct ranges; do you take selenium to help with conversion?

4 likes
Reply

Above where they started when I was first diagnosed (5.4) I think and in upper quarter of range.

My results on 88.5mcg were:

Tsh 2.52 (0.27-4.2)

Ft4 14.7 (12-22)

Ft3 3.78 (3.1-6.8)

Then these above were on 100mcg. I'm now on 112.5 x

Reply

These results are similar to mine and I am on 200 mcg T4 and 20 mcg T3. I feel fine on them but I also have B12, vitamin D deficiency and anaemia.

I only have a partial non working gland which I was born with.

Reply

There are severe possibilities: Unconverted T4 increasing levels of rt3; low ferritin making conversion poor; low Folate; low Vit D; and low B12 - this is the one that doctors all too often miss as they are misguided on normal range; too much thyroid antibody stimulation which can be addressed by removing triggers; low Selenium which makes us more vulnerable to antibody attack. On top of all this there is the timing of meds and supplements to consider as well! We don't get a manual. ;-)

1 like
Reply

Ferritin has to be extremely low to impair T4 to T3 conversion. If this were the case TSH would be very high as the pituitary would be unable to convert T4 to T3 and so couldn't respond to T4 levles.

1 like
Reply

Provided that pituitary was working correctly, which it might not be.

1 like
Reply

My AM blood cortisol came back slightly raised last week. But gp or endo said normal and no more investigations needed x

Reply

'Provided that pituitary was working correctly, which it might not be.'

true.

Reply

Definitely get Vit D, B12, folate and Ferritin tested as well. If these aren't optimal then you need to supplement as these help yourcthyroid to work better, can improve conversion issues and can rid you of some symptoms. Throwing T3 into the mix isn't necessarily the best way to go.

Reply

It's good to check the above vitamins / minerals because they are often low in hypothyroidsism. However, I'm not aware of any evidence that the sort of deficiencies normally encountered affects conversion, this seems to be a concept that originated long ago and get perpetuated. If conversion is affected by deficiencies it will have a major effect on pituitary response to T4 and the TSH will be very high.

Reply

Thanks everyone.

Sorry should have said my vits are good. On b12 Injections so that's high, vit d 112, ferritin 68.5 (prev had high iron when it was at 70 so can't supplement), folate only one on the low side at 9 (2.91-50) (but I get it prescribed and I've been better at taking it since)

My results on 88.5mcg were:

Tsh 2.52 (0.27-4.2)

Ft4 14.7 (12-22)

Ft3 3.78 (3.1-6.8)

That's the lowest my t3 has been since diagnosed. Then the results above were on 100mcg. Now on 112 mcg.

On 100mcg and gf my antibodies reduce so tpo is back in range and tgo is 137 (0-115) down from 565 when I first diagnosed

I'm reluctant to reduce back down to 88.5mcg because I felt like crap. I doubt he's going to give me any t3. Maybe that's why he wanted me to test rt3 I don't know.

I just wondered if high rt3 can make you feel rubbish x

Reply

It worked for me! Mine were pretty low , well 3 out of the four and folate took a year to get up but it reversed my conversion so I was then able to go back onto NDT which is what I was firstcput on many many years ago. My only may be difference from others is that I don't have anti bodies but I do have a very poor diet as have loads of food intolerances which I can't totally work around as so many.

Reply

Salphy, There's quite a difference between the two blood test results which would not be explained by the small change in dose. When there is autoimmune hypothyroidism the thyroid output can vary substantially as it gets attacked by antibodies. Eventually this settles down as the thyroid packs in. Pushing your fT4 high (with levothyroxine) will increase your rT3 levels which will not help. I'd be inclined to stick with 100 mcg for a few months and if you don't feel better ask for some L-T3. It's a long time ago but I remember when I was on high doses of L-T4 my response was irratic, it seemed that fT4 tended to build up and would suddenly decide to work for a while - no science behind this, just how it seemed at the time.

2 likes
Reply

That seems like me. On 75mcg I felt good but then after about 12 weeks went downhill again.

I had an ultrasound that showed v.small thyroid gland.

The thing i don't get though is my antibodies have kept reducing with the increased Levo. My tpo is now in normal range and tgo only a little high at 137 (0-115)

So it looks like there should be little activity from them at the minute. Unless that's why my results shot up. But then I really don't feel better.

He wants me to retest after 4 weeks on 112.5mcg with rt3 too. I might give it a bit longer. I don't know I just feel crap either way x

Reply

I don't know but I suspect variations in thyroid output are due more to the state of the thyroid than antibody levels per se. Many people have high antibody levels but no thyroid problem, it more due to how the thyroid responds to antibodies. I'm only guessing but perhaps once the thyroid has started to fail and has been damaged it progresses until it packs in. I would adjust you dose to the level where you feel best. Measuring fT3 won't have much value but if it gets you appropriate treatment then it might be worth it. It becomes a tactical assay rather than one of cliical value!

1 like
Reply

Does seem abit odd, bumping you up from 100 to 112.5 mcg when your T4 was over range at 100mcg, and that( whether as RT3) was causing problems. Unfortunately might have to do as endo says to get T3 prescription, and get tested for RT3 which I think most of us believe will have gone up in blood tests, while your T3 result will still not be 5.

Reply

Not sure what to do. I pay £140 a time to see him + blood tests. Considering going it alone.

The only positive is he writes to my gp and they give me the dose he recommends on the nhs x

Reply

Must admit at those prices I would consider going it alone. Even if endo gives you a prescription for T3 wonder if the surgery will honour it due to great expense, might give you a trial, then have to find your own source. You know the protocol of a increasing doses, and probably about adding T3 slowly, then checking bloods. I would think, with advice from the fantastic forum members, you could try it yourself.

1 like
Reply

Hi Salphy,

it does seem your results are in the higher ranges or above and to me, you are over medicated on T4. I do agree that perhaps you need to lower your dose initially before requested T3 meds just to see if the results change. Please tell your GP/Endo what you are doing though.

When they were messing me around many moons ago, I was told by one GP quote "Too much T4 is bad for your heart, but if your ranges are too low, they will put you on the higher dose anyway" which to me is a contradiction and a load of rubbish.

Just be aware that to get T3 especially Lithyronine in the UK is difficult for a new patient, because of the price (very sore subject).

It might be that you might be low in Vitamin D and B12 if you are tired. Also might be anaemic especially if you suffer with heavy periods etc.

Most meds do take a little while to absorb properly.

When you are next due for blood tests, do not take the meds before the test, only after and never take the thyroid meds with other meds. Leave a few hours between.

Take care :)

Reply

Thanks. I have b12 injections and take vit d and folic acid. OK ferritin slightly high iron which they said is healthy high.

My results on 88.5mcg Levo were

Tsh 2.52 (0.27-4.2)

Ft4 14.7 (12-22)

Ft3 3.78 (3.1-6.8)

And I felt rubbish so don't want to reduce :-/

Reply

I would ask to be referred to a Endo then and get a second opinion. Some are good and some are not. It could be that you are not converting well especially if you are feeling rubbish.

Depending where you are, you should get a referral soon. Just demand a referral with your GP as you are entitled to see a Consultant. Some GP's are reluctant, but most, do not understand what it is like to have a thyroid condition.

Let us know how you get on.

:)

1 like
Reply

Thanks I was referred in January have an appointment late June but not hopeful. Heard bad reviews of them. That's why I went private to avoid the 5 month wait and see someone who doesn't just look at tsh x

1 like
Reply

I completely understand that. When I was having my troubles, it was my Gynaecologist that referred me to a Endo. My then GP had reduced my T4 from 200 mcg to 75 mcg - so you can imagine what state I was in. My medication gradually increased until I reached the 200 mcg again, which is what I call my natural dose (always was on that dose from an early age) and due to the damage and problems the lower dose had created, T3 was introduced on top of it. I have been on it for about 16 years. My last Endo which was a NHS one tried to take me off it because of the price. But I refused and also my results have proven that I need it. I know I may be on borrowed time, but hopefully safe for another year.

Best of luck and I hope you get the help and guidance you need.

I have just had another look at the results you added to your post and I think I have said, they are similar to mine. The T4 is in the lower part of the range. So an increase is likely. (I apologise that I may have misread a previous post).

Always here for a chat. :)

Reply

Thank you. Hope you manage to keep your t3.

Sorry they were my results on 88.5mcg

I was then increased to 100mcg which is the results on the first post where my t4 was over range

Now increased to 112.5mcg so will be even more over x

Reply

I think you will most probably/potentially end up on doses between 125-175 mcg. :)

Reply

Hello Salphy. Just looking at your levels they are very similar to mine prior to me starting T3 meds. I continued to suffered fatigue when my FT4 was above range but my RT3 was low still. I was not a poor converter but I was convinced T4 meds made absolutely no difference to my symptoms. My FT3 only began to rise when my vits/mins were at a decent level, just as indicated on this forum. Been on on T3 meds for the last 3 months and although my FT3 level is not much better than prior to beginning T3, I feel so much better. I have no idea why this is. I now take 25mgs Levo and 25mgs T3. Seems to have hit the spot. You know leveling is very individual and how these medications work is so complex. Keep trying until you feel better and you will! All the best.

1 like
Reply

You may also like...